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- Open Access
PReS-FINAL-1009: Antioxidant superoxide dismutase activity is paradoxically normal in juvenile systemic lupus erythematosus
© Radziszewska et al.; licensee BioMed Central Ltd. 2013
- Published: 5 December 2013
- Systemic Lupus Erythematosus
- Juvenile Idiopathic Arthritis
- Juvenile Idiopathic Arthritis Patient
- Juvenile Systemic Lupus Erythematosus
- Nitrative Stress
Damage via generation of free radicals has been implicated in the pathogenesis of systemic lupus erythematosus (SLE). Numerous studies demonstrate both direct and surrogate evidence for a high burden of oxidative and nitrative stress which parallels disease activity. Antioxidants such as superoxide dismutase (SOD) function to protect against oxidative damage by neutralizing free radicals and levels are typically elevated in situations of high oxidative stress.
To examine the activity of the antioxidant enzyme SOD in patients with the juvenile onset SLE (JSLE).
Serum was obtained form 49 patients with JSLE attending the adolescent rheumatology clinic at University College London Hospital, 166 juvenile idiopathic arthritis (JIA) disease controls, and 17 healthy adolescent controls (median age at sampling 19.02 [IQR 17.00-20.67], 16.37 [IQR 10.41-18.04], and 14.78 [IQR 10.22-23.03] respectively). Median duration of disease was 8.00 [IQR 4.42-10.38] years for JSLE and 6.30 [IQR 2.41-10.96] years for JIA. Female: male ratio was 41:8 (83.7% female) in JSLE patients, 95:71 (57.2% female) in JIA patients, and 11:5 (64.7% female) in HC. SOD activity was measured using a commercial colorimetric assay.
Surprisingly, no statistically significant difference in SOD activity was observed between JSLE (median = 4.04 U/ml [IQR 2.79-8.06]) and healthy controls (median = 4.03 U/ml [IQR 2.18-6.48]) though SOD activity was raised in patients with JIA (median = 6.38 U/ml [IQR 4.83-8.70]) compared to controls and JSLE (p = 0.0009 and p = 0.0036 respectively). There was also no difference in SOD activity when JSLE patients were subdivided into serologically active and inactive disease groups based on complement 3 and anti-double stranded DNA antibody levels. Moreover, SOD activity levels did not vary with organ involvement and remained normal in patients treated with disease modifying antirheumatic drugs (DMARDs) or a combination of DMARDs and steroids.
Given the established role of oxidative stress in pathology of SLE, it is surprising that SOD activity is not elevated in our cohort of JSLE patients. A blunted antioxidant response may have aetiopathogenic implications that warrant further investigation. Multivariate analysis to correct for factors that may differ between the groups, such as prednisolone use, are underway.
This article is published under license to BioMed Central Ltd. This is an Open Access article distributed under the terms of the Creative Commons Attribution License (http://creativecommons.org/licenses/by/2.0), which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited. The Creative Commons Public Domain Dedication waiver (http://creativecommons.org/publicdomain/zero/1.0/) applies to the data made available in this article, unless otherwise stated.